Electron microscopy leads to the resolution of a prolonged case of microsporidial keratitis

The use of electron microscopy by corneal surgeons can facilitate diagnosis in difficult cases. At Cleveland Clinic’s Cole Eye Institute, electron microscopy led to the resolution of a prolonged case of microsporidial keratitis after cataract surgery in a 70-year-old immunocompetent male who had been referred for evaluation of chronic unilateral keratitis and iritis.

Presentation:

Punctate keratitis and iritis had been noted within two weeks after uncomplicated cataract surgery at another facility, and progressed to an epithelial defect and presumed herpetic kerato-uveitis contiguous with the temporal cataract wound.

The patient experienced multiple flare-ups over two years that responded well to topical steroids. However, their use led to ocular hypertension.

Treatment:

The patient underwent penetrating keratoplasty and Baerveldt shunt placement at the Cole Eye Institute. Subsequent electron microscopy testing, performed by James McMahon, PhD, in Anatomic Pathology, revealed the presence of microsporidial stromal keratitis that had been missed previously with traditional microscopy. Cornea surgeon William J. Dupps Jr., MD, PhD, notes that no evidence of recurrence was seen in the graft after postoperative treatment with topical fumagillin and oral albendazole.

Outcome:

The patient’s vision corrected to 20/20 with a rigid contact lens. He is a hobby pilot and was able to resume flying after a long hiatus due to his vision problems.

Discussion:

Cataract surgery and local immunosuppression from the topical steroids were the only identifiable risk factors in this unusual case, notes Dr. Dupps. The clinical presentation can overlap with herpetic kerato-uveitis or infectious crystalline keratopathy and delay diagnosis and appropriate management.

“Getting this diagnosis enabled us to appropriately utilize a more suitable antimicrobial to treat the patient’s chronic infection and prevent recurrence in the graft,” he says. “Being able to decrease his steroid use through better control of the infection also was important for giving him relief and allowing us to better manage his postoperative medications.”

“While electron microscopy is not a new technology, its use in this case demonstrates the value of a less commonly utilized advanced diagnostic technique,” he concludes.